Habitat use and movements of canvasback broods in southwestern Manitoba

Abstract

Canvasback (Aythya valisineria) broods (n = 69) accompanying marked females were observed during five summers in southwestern Manitoba. We evaluated movements of broods of different age classes ( 14 days old, 15-28 days old, and >28 days old) among ponds of different size and wetland class. Of 202 brood sightings, 7% occurred on seasonal ponds, 81% on semipermanent ponds, and 12% on permanent ponds. Pond size ( 0.2 ha vs. >0.2 ha) was a significant factor in brood use whereas wetland class was not. Canvasback broods used larger ponds as brood age class increased. Broods moved an average of 195 m between sightings. Eighty-three percent of broods observed within seven days of hatching (n = 46) had moved from the nesting pond. No significant differences in frequency or distance of movements were detected among years or among brood age classes. Extensive movements among ponds of various sizes and classes emphasize the importance of wetland complexes for providing diverse habitats needed for nesting and brood-rearing canvasbacks.